With the increasing trend to minimum or zero tillage seeding practices, much work has been done in the design of a ground engaging tool. This tool must open the soil and provide an optimum placement for the seed, preferably maximizing moisture, consistent and accurate soil coverage, and adequate displacement of fertilizer. Those openers that provide a separation of seed and fertilizer are called “double shoot” openers, as these openers require a dual delivery system to maintain proper separation between the seed and the fertilizer. The double shoot opener design typically creates a separate groove within the furrow formed in the soil to accept the two commodities. With increasing amounts of fertilizer being applied during planting operations, and with the unpredictable fracturing of soils due to variations in moisture content and malleability, the seed is often comprised with too much contact with raw fertilizer, causing the seed to be burned and preventing the seed from germinating.
This problem has been addressed by manufactures of planting implements by providing an extra set of openers between every second seed row, placing seed, for example, at 10 inch row spacings and having two adjacent seed rows feed off a single fertilizer row between the two seed rows, thus assuring adequate separation between the seed and the fertilizer. This configuration of a fertilizer row between every second seed row is called “mid-row banding”. The seed rows are formed with furrows or grooves that are three to four inches for proper soil utilization and, as a result, there is significant soil disturbance. Furthermore, the rearmost rank of openers does not typically get as much “fall-back” of soil to cover the seed properly because there is no subsequent rank of openers that throw soil over to that row. This problem has also bee addressed by the installation of harrow tines that are operable to shift soil into the last formed seed row. With all of these openers and harrow tines, there is a substantial draft requirement for such an implement, requiring a substantially sized tractor to pull the implement. Furthermore, there is a significant loss of ground cover which contradicts the general principles of zero or low till planting operations.
Most shank-type seed drills are configured with three or four ranks of openers supported by wheels ahead of the front rank of openers and a row of press wheels behind the rear rank of openers. The distance between the wheels ahead of the front rank and the press wheels behind the rear rank is sufficiently large as to be subject to ground elevation irregularities that lead to inaccuracies in the depth at which the seeds are placed into the ground. Furthermore, the distance between the ranks of openers can cause misalignment when the drill slides to one side during side hill operations, often causing two seed rows to coincide and the press wheels to miss the row they were positioned to be packing.
Large implements of typical wing-up transport design are very bulky to transport over the public highways, interfering with other vehicular traffic and being jeopardized by overhead wires and highway overpasses. Accordingly, it would be desirable to provide an improved transport configuration for large implements to provide a more compact transport configuration without sacrificing operational requirements.
Accordingly, it is also desirable to provide a press wheel structure that are adjustable to vary the effect thereof for directing soil inwardly to cover seed rows.